Next-Generation Sustainable Lightweight Fatigue-Critical Components Research

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There has been a two decade-long revolutionary changes in transportation vehicle structure light-weighting to address the need for better fuel economy. Despite the progress made by introducing aluminum alloys into structural components, light-weighting attempts still fall short to meet the drastic fuel efficiency targets. To maximize the use of lightweight materials in the vehicle body structure, a recent concept of multi-material lightweight vehicle architecture has emerged. This concept calls for the use of the lightest material with the best performance in the location used. ***Being 75% lighter than steel and 35% lighter than aluminum, magnesium alloys have shown an excellent fatigue performance that nominates them as a viable replacement for fatigue-critical components, components with fatigue strength as their key performance indicator like the engine cradle in a car, or the wing-fuselage attachment lugs in airplanes. When compared to aluminum alloys like A356 or AA6082 currently employed in similar components, magnesium alloys like ZK60 outperform aluminum fatigue behavior. However, there is a major scientific gap in the current literature in addressing the feasibility of such applications for magnesium alloys. The objective of the proposed research is to develop knowledge base, and enabling technologies for the application of magnesium alloys to fatigue-critical parts of transportation vehicles with the ultimate goal of designing next-generation sustainable lightweight components. ***Due to their superior specific strength, wrought magnesium alloys are better candidates for load-bearing components. However, beside the yield asymmetry inherited by HCP micro structure, they show directional anisotropy induced by the severe plastic deformation involved in their manufacturing process. The cyclic behavior of newly developed wrought magnesium alloys in different directions under multi-axial fatigue loading will be studied and the enabling design models will be developed in this research. ***The proposed research is a first of its kind in examining the suitability of the lightest structural metal for next-generation fatigue-critical components. The transition from cast iron to steel stamping; and steel stamping to aluminum alloys each required nearly two decades. It is expected that the transition from current aluminum alloys to next-generation lightweight counterparts will also require about the same time. Therefore, the proposed research is right in timing to develop the knowledge and enabling technologies required for the next-generation components that are expected to become market-ready in the next decade to address the targeted fuel efficiency on time. With transportation vehicle manufacturing accounting for 30% of Canada's trade it is expected that the innovation developed through the proposed research ensure that Canada remains competitive in the future market.